Prepare v0.1.2 CI and portfolio documentation

[ludioo]

Summary

Prepares Project Health Check for Unity v0.1.2 as a quality-infrastructure release.

Changes

• Add the live EditMode Tests badge to the README
• Document automated CI and retained test artifacts/logs
• Add the v0.1.2 changelog entry
• Update package metadata to 0.1.2
• Record the completed CI milestone in the roadmap
• Update the tagged UPM installation URL

Scope

This release contains documentation and CI infrastructure updates only.

• No production code changes
• No scanner behavior changes
• No new package dependencies
• Existing GitHub Actions workflow unchanged

Validation

• Existing EditMode workflow has completed successfully
• Unity version remains 2022.3.23f1
• Workflow continues to run EditMode tests only
• No credentials or secret values are included
• Package, changelog, and installation versions are consistent